Hydrogenation of crotonaldehyde



' Patented Sept. 15, 1931 UNITED STATES PATENT" OFFICE LLOYD CLAYTON SWALLEN, OF TERRE HAUTE, INDIANA, ASSIGNOR TO COM'MERCIAL SOLVENTS CORPORATION, OF TERRE MARYLAND No Drawing.

This invention is a process of making butyraldehyde or butyl alcohol or both simultaneously, by the hydrogenation of crotonaldehyde. The process may be illustrated by the following equations (1) CH CH CH.CHO H,=CH .CH .CH .CHO

CrotOnic aldehyde Butyrald'ehyde 2 crncmcnzcno H,=cH..oH..cH,.cH2on Butyraldehyde Butyl alcohol a small quantity of by-products is formed.-

The by-products ordinarily obtained-in the hydrogenation are reaction products of butyraldehyde, either with itself or with butyl alcohol. Butyl butyrate and dihutyl butylal are two by-products that are ordinarily obtained in rather large quantities and one of the advantages of the present invention lies in the prevention of the formation of substantial quantities of these impurities.

In preparing a catalyst for use in the process, ordinary sodium silicate, l1qu1d, 1n 49 Beaum solution is diluted with 10 timeslts weight of distilled water. A 10% solution of copper nitrate is prepared and is grad-' ually added to the sodium silicate solution at ordinary temperature and with constant stirring until precipitationis complete. The precipitate is then recovered from the mature by filtration, using suction to remove as much liquid as possible. The resultant filter cake is dried in the air at ordinary temperatures until the material sets to form a rather hard, brittle mass. The mass is then pulverized and screened to produce a cata- B Jlyt-ic material of about 814 mesh. The

granules are washed thoroughly by boiling them with distilled water for an hour, draining, and then re-washing them several times with cold distilled water. The catalyst is HAUTE, INDIANA, a CORPORATION or HYDROGENA'I'ION OF CROTONALDEHYDE Application med November 7, 1927. Serial No. 231,781.

the catalyst at a rate of 1.7 g. crotonaldehyde I vaporized per 0. c. of catalyst per hour, the product obtained contains less than 4% of high-boiling impurities. The product is recovered by passing the mixture leaving the catalyst thru an ordinary water condenser to liquify it. Under these conditions, the efiluent gas from the condenser is practically pure hydrogen. If the molecular proportion of the reacting ingredients is adjusted so that there is a large excess of hydrogen, for example, about 5 mols. of hydrogen to 1 mol. of croton aldehyde, the product obtained is about butyl alcohol and 10% butyraldehyde. By increasing the space velocity and using molecular proportions of the reacting ingredients, one may obtain a product which consists very largely of butyraldehyde, having only a small proportion of butyl alcohol.

While 170 C. has been described as the optimum temperature for catalysis, the catalyst is active over a wider range, and temperstures between 120 and 200 C. may be use In practise of the process it is not necessary to make a preliminary reduction of the catalyst with hydrogen. The washed granules maybe used directly with good results. However, the. activity of the catalyst is increased ifit is given a preliminary reduction by passing pure hydrogen thru it at about 350 C. and I prefer to follow this latter procedure. The catalyst is preferably reduced in the apparatus in which it is later to be used.

In the preparation of the catalyst the reaction which occurs when copper nitrate is added to sodium silicate is presumed to prothen again dried in the air at room temperaduee copper silicate and sodium nitrate. The i sodium nitrate is soluble and is removed from the catalyst during the preliminary washing. It is quite possible that during the prelimi- 5 nary reduction of the catalyst, if this is done, or during the first few moments of use in the process, the copper silicate catalyst may undergo some further chemical change. For example, a mixture of finely divided silica and copper may be the final result. Indeed it is possible that the primary reaction of copper nitrate and sodium silicate may produce a product comprising hydrated copper oxide and hydrated silicon dioxide, altho this is considered improbable. In place of copper nitrate, other salts of copper, such as the chloride or sulfate may be used in the preparation of the catalyst. In any event, the term copper silicate as used in the appended claims is intended to describe and is limited to the reaction product of a soluble copper salt and sodium silicate as described in this specification.

Now, having fully described my invention, I- claim the following as new and novel:

1. A catalyst for the hydrogenation of crotonaldehyde comprising precipitated copper silicate which has been reduced by hydrogen.

2. A catalyst for the hydrogenation of crotonaldehyde comprising the insoluble reaction product of sodium silicate solution with a soluble copper salt. said reaction product having been reduced by hvdrogen.

8. A catalyst for the hydrogenation of crotonaldehyde comprising the insoluble reaction product of sodium silicate solution with copper nitrate, said reaction product having been reduced by hydrogen.

a 4. A process of preparing a catalyst which comprises adding a solution of a copper salt to sodium silicate solution until precipitation is complete, filtering. washing, and drying the product, and reducing said product in an atmosphere of hydrogen at a temperature of 120200 C. t

5. A process of preparing a catalyst which comprises adding a solution of copper nitrate .to sodium silicate solution until precipitation is complete, filtering. washing. and drying the product, and reducing said product in an atmosphere of hydrogen at a temperature of 120-200 C.

6. A process of preparing a catalyst which 35 comprises adding a solution of copper nitrate to sodium silicate solution until precipitation is complete, filtering, washing, and drying the product, and reducing said product in an atmosphere of hydrogen at an elevated temperature' below red heat.

In testimony whereof I aflix in Si ature.

LLOYD CLAYTON SW N. 

